Hello, yesterday i tried this problem,without success: Bobbys Bet

To find the expected value i arrived with that formula:

where :

S = number of sides of the dice.

R = min number that we can take.

X = times we need take at least number R.

Y = times we can roll the dice.

W = Bet Payment.

(All are input variables)

this is my code that gives WA:

Code

I really appreciate your help.